Power-operated retractable ladder for pleasure boats

ABSTRACT

A boat ladder for pleasure boats to enable a user to easily get into or out of a boat when in the water and also get into and out of the boat when loaded on a transporting trailer, including a movable section and a stationary section supported from the boat hull, together with an interconnection with the movable section to move it from an extended position to a retracted position.

United States Patent 11 1 Hovey Nov. 27, 1973 1 POWER-OPERATEDRETRACTABLE 599,666 2/1898 "1116mm" 182 206 LADDER FOR PLEASURE BOATS3,033,309 5/ 1962 Fugere.... 182/195 3,061,042 10/1962 Giles 182/ 195[76] Inventor: Cecil Carlton Hovey, PO. Box 626, 2,860,822 11/1958 Smith182/93 Maitland, Fla. 32751 2,650,750 9 1953 Chesney.. 1. 182/2083,464,517 9 1969 Ak 182 22 Flled: Sept. 9, 1971 195 [21] Appl. No.:179,049 Primary ExaminerReinaldo P. Machado Attorney-Clarence A. OBrienet a1.

[52] U.S. Cl 182/91, 182/88, 182/97, M

182/208, 182/195, 9/1 [57] A851 CT 51 Int. Cl. B631) 29/20, E060 5/06 Aboat ladder for Pleasure boats to enable a user to [58] Field 61 Search182/97, 95, 208, easily get into or out of a boat when in the Water and182/86, 91, 195; 105/443, 44 4 9/7 1 also get into and out "of the boatwhen loaded on a transporting trailer, including a movable section and a[56] References Cited stationary section supported from the boat hull,to- UNITED STATES PATENTS gether with an interconnection with themovable sec- 586 012 7/1897 C be" 105/447 tion to move it from anextended position to a reamp 3,285,367 11/1966 Brodie 182/97 actedposmon 3,039,562 6/1962 Wagner 182/91 10 Claims, 15 Drawing FiguresPATENTEBuuv 27 I973 SL517 1 [IF Cecil Car/ton Hove) [X I" ENTO K. 40%.

39174.net)

' PATENTEDNUYN I973 Cecil Car/fan H0 vey POWER-OPERATED RETRACTABLELADDER FOR PLEASURE BOATS BACKGROUND OF THE INVENTION 1. Field of theInvention The present invention generally relates to a boat ladder forpleasure boats and more particularly a poweroperated boat ladder tofacilitate access into the boat as well as egress therefrom whether theboat is in the water away from a dock or supported on a transportingtrailer or other supporting structure with the ladder including astationary section mounted on the boat hull and a movable sectionmovable in relation to the stationary sectionand power-operated meansconnected with the movable section to move it between retracted andextended positions.

2. Description of the Prior Art Pleasure boat users who wish to get intoor out of pleasure boat when the boat is in the water have alwaysexperienced considerable difficulty. When such boats are alongside of adock, there is no particular problem. However, when the boat is in thewater and away from the dock, it is quite difficult to ascend from thewater into the boat or to get from the boat into the water in a safe andconvenient manner. Also, when the boat is on a transporting trailer, itis also quite difficult to get into the boat or exit from the boat.While some attempts have been made to overcome this problem by the useof ladders which usually are attached to the gunwale of the boat andwhich swing from a position interiorly of the boat to a positionalongside the hull, such devices require manual manipulation thereof bya person in the boat to pivot the ladder to an external position andalso occupy some of thespace within the interior of the boat.

SUMMARY OF THE INVENTION retractable device utilized for ascending intoa boat or descending out of a boat when the boat is in the water awayfrom the pier or is loaded on a transporting trailer, thereby greatlyfacilitating the functional utility of a pleasure boat when used bywater skiers, divers, swimmers, underwater workers, or others employingthe pleasure boat and desiring to enter and exit from the boat.

Another object of the present invention is to provide a boat ladder forpleasure boats that may be installed at the stern, side or bow of theboat according to the desires of the manufacturer or owner.

A further object of the invention is to provide a boat ladder forpleasure boats that will include permanent mounting and stowage whichmay include a housing for out-of-sight stowage to present a structurewhich does not interrupt the general lines and configuration of thepower devices, such as an electric motor, manually extended by theweight of the user and spring returned, or any combination of such powerdevices.

Still another important feature of theinvention is to provide a boatladder for pleasure boats in which the ladder includes a movable sectionwhich may be longitudinally extended or retracted or pivotally extendedor retracted.

Yet another important feature of the invention is to provide a boatladder for pleasure boats in accordance with the preceding objects whichis effective for providing a safe and dependable boat ladder, easilyincorporated into pleasure boats or added to existing pleasure boats,and relatively inexpensive to manufacture, operate and maintain.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of aportion of a pleasure boat hull with one embodiment of the boat laddermounted thereon;

FIG. 2 is a vertical sectional view of the boat ladder illustrating thestructure for extending and retracting the same;

FIG. 3 is a side elevational view of another embodiment of the boatladder;

FIG. 4 is a vertical sectional view taken substantially upon a planepassing along section line 44 of FIG. 3 illustrating the structuraldetails of this embodiment of the invention;

FIG. 5 is a fragmental sectional view illustrating the structure of aposition-locking device for maintaining the ladder in a fully extendedor retracted position when power is not being applied;

FIG. 6 is an elevational view with portions in section illustratinganother embodiment of the boat ladder .with a reciprocating movablesection;

FIG. 7 is a vertical sectional view taken substantially upon a planepassing along section line 7-7 of FIG. 6- illustrating furtherstructural details of this embodiment of the invention;

FIG. 8 is a side elevational view of another embodiment of boat ladderfor pleasure boats illustrating a pivoted movable section;

FIG. 9 is a perspective view of the construction of FIG. 8;

FIG. 10 is a perspective view of another embodiment of the boat ladderemploying a hinged movable section;

FIG. 11 is a side elevational view of the construction of FIG. 10illustrating the movement of the movable section;

FIG. 12 is a rear elevational view of the construction of FIGS. 10 andI1;

FIG. 1 is an elevational view of another embodiment of the boat ladderwith a hinged or pivoted movable section illustrating a manner in whichthe structure is built into the hull;

FIG. 14 is a detailed vertical sectional view of the construction ofFIG. 13', and

FIG. 15 is a schematiic view illustrating a representative power circuitfor energizing the power mechanism for extending and retracting the boatladder.

DESCRIPTION OF EMBODIMENTS Referring now specifically to the drawings,FIGS. 1

and 2 illustrate a boat ladder generally designated by reference numeral20 that is telecoping and fully power-operated and is mounted on thestern 22 of a pleasure boat and includes a stationary section 24 and amovable section 26.

The stationary section 24 includes a plurality of brackets 28 that maybe anchored to the boat hull in any suitable manner and which may beconveniently of tubular construction. Mounted on the outer ends of thetubular brackets 28 is a pair of substantially vertically disposedtubular members or cylinders 30 which are I closed at their upper ends,as indicated by numeral 32,

and open at the bottom ends thereof to define a fluidpressure receivingcylinder which has conduits 34 and 36 communicated therewith with theconduit 34 being communicated with the upper end of the cylinder and theother conduit 36 communicated with the lower end thereof immediatelyabove a closure-forming member 38. The two tubular members or cylinders30 are rigidly interconnected by members 39 which form ladder rungs andwhich also rigidly interconnect the tubular members or cylinders 30.

The movable section 26 includes a pair of tubular members 40 whichlongitudinally telescope in relation to the lower end portions of thetubular members 30, as illustrated in FIG. 2. The upper end of eachtubular member 40 is provided with a piston rod 42 connected theretowhich extends through the closure member 38 and is provided with apiston 44 on the upper end thereof which is reciprocal between the upperclosed end 32 and the closure member 38 which forms a cylinder forreceiving the piston 44 so that the piston 44 will be reciprocatedeither downwardly or upwardly depending upon the admission or exhaust offluid pressure above or below the piston 44. The lower ends of thetubular member 40 are interconnected by a member 46 which generallyparallels the members 39 and which forms a ladder rung spacedsubstantially the same distance from the lower member 39 as the lowermember 39 is spaced from the upper member 39 when the members 40 are intheir extended positions. As illustrated, even when the movable section26 is extended a substantial portion thereof is still received in thelower end of the tubular members 30 for effective guiding supportthereof; Fluid pressure, such as hydraulic pressure, is supplied by ahydraulic pump and motor unit 48 provided with suitable controls foreither extending or retracting the movable section.

The stationary section 24 is configured and constructed and installed ina manner to be clear of the water or it may be constructed in a mannerto offer very little resistence during high speed operation of the boat.It is permanently mounted on the boat in any suitable manner and onceinstalled will remain in position. If necessary, an adjustable bracketstructure may be provided for orienting the boat ladder in the desiredvertical orientation so that the device may be installed on boat hullshaving varied hull configurations. Usually, two affixed bars or rungs 39are adequate but this may be varies depending again upon the verticaldimension of the hull. Also, the movable section is provided with onebar or rung 46 but this may also vary depending upon the desires andrequirements for each individual owner or user of the boat. When themovable section is extended, at least one step or bar is placed in thewater or beneath the bottom of the boat hull when fully extended. Whenfully retracted, the movable section will not interfere with operationof the boat or with transporting the boat on the trailer or with loadingthe boat on or off the trailer since it is above the bottom of the hull.

Referring now specifically to FIGS. 3 and 4, a boat ladder similar inoperation to that of FIGS. 1 and 2 is illustrated but this device ismounted in the side or bow of the boat hull and is enclosed for hiddenstowage when retracted. This embodiment of the boat ladder is generallydesignated by numeral 50 and is illustrated in built-in arrangementalong the inner surface of the side 52 of the boat hull and alsoincludes a modification of the bottom 54 of the boat hull which has arecess 56 formed therein. the boat ladder includes a stationary section58 and a movable section 60. The stationary section 58 includes ahydraulic pump and motor assembly 62 having a pair of depending guidemembers rigid therewith which may be in the form of fluid pressureoperated double acting piston and cylinder assemblies 64 provided withan axially extending piston rod 66 having an attachment 68 on the lowerend thereof.

The movable section 60 includes a pair of tubular members having thelower ends thereof closed and interconnected by a transversely extendingstep, bar or rung 72. The cylindrical tubular members 70 telescopinglyreceive the cylinders 64 and the interior of the cylindrical members 70include a partition 69 anchored to attachment 68. The external surfaceof the cylindrical tubular members 70 are slidably received and guidedthrough apertures 74 in the recess 56 which is shaped to receive thetransverse bar or step 72 when retracted. A guide member 76 may beprovided on the cylindrical members 70 to guide the movement thereof andsuitable hydraulic conduit structures may be incorporated to providefluid pressure to the cylinders 64 to extend and retract the movablesection 60. Thus, the step 72 when retracted will form a continuation ofthe external surface of the hull, thereby eliminating any possibleinterference with its passage through the water.

In some boats which may have a high freeboard, an additional step may benecessary on the hull thereon between the movable step 72 and thegunwale 78 and this step may be rigidly fixed to the hull in anysuitable manner and is not shown in FIGS. 3 and 4. Rather than providinga projecting step, a recessed step may be formed directly into the hull.Also, this type of construction is especially adapted for boats havingrelatively low freeboards and is best installed into the boat hull atthe time of fabrication thereof. If desired, the boat hull may beprovided with a recess or compartment for receiving the entire boatladder assembly which may be in the form of a preassembled cartridgetypeinsert which may be merely inserted into the recess or chute or otherstructure provided therefor and secured in place.

FIG. 5 illustrates a structure for maintaining the movable sectionstationary in relation to the stationary section when either in itsextended or retracted position when no power is being applied. Suchdevice includes a detent 80 spring biased inwardly by a spring 82received in a housing 84 carried by an external tubular member 86 forengaging a recess or notch 88 with cam surfaces and telescoping member90. This arrangement may be employed on any of the telescopingembodiments of the ladder.

FIGS. 6 and 7 illustrate another embodiment of the telescoping form ofthe boat ladder which is manually extended by the weight of the user andspring returned. This embodiment of the ladder is generally designatedby numeral 92 and includes a pair of stationary tubular members 94interconnected by transverse bars, steps, or rungs 94 with the tubularmembers being connected to the boat hull 98 by brackets 100. The movablesection includes a pair of tubular members 102 that telescope into thetubular members 94 with the lower ends of the tubular members 102 beinginterconnected by a transverse bar, rung or step 104 which may be in theform of a tubular member. The tubular members 102 have an extendingpiston rod 106 connected thereto which extend upwardly through astationary partition 108 in the tubular member 94 and terminates in aflange or piston 110 slidably movable within the tubular member 94. Acompression coil spring 112 is disposed between the flange 1 and thepartition or-abutment flange 108 to spring bias the bar or step 104upwardly. Thus, when a sufficient force is applied to the movablesection in a downward direction to overcome the springs 112 or otherresilient or elastic material, such as occurs when a user steps on or,otherwise pulls down on the step 104, the movable section will descendinto the water or beneath the boat. Whenever the downward force isremoved, then the movable section will be automatically retracted by thesprings or other resilient material. A dampening device, such as a smallorifice, l 14 may be provided ajdacent the upper end of the tubularmembers to control flow of air and thus cushion the upward movement ofthe flange or piston 110 when moving upwardly thereby providing timedretraction of the movable section.

FIGS. 8 and 9 illustrate another form of the boat ladder generallydesignated by numeral 120 which includes a stationary section 122 and amovable section 124 with the stationary section 122 including a pair ofside pieces or stiles 126 interconnected by a plurality of steps or bars128 positioned to enable a person to descend or ascend between the deckor gunwales of the boat and the movable section. Bracket assemblies 130which may be adjustable and attached to the boat hull in any suitablemanner may be provided for mounting the stationary section 122 attachedto the stern 132 of the boat hull. The movable section 124 also includestwo side members or stiles 134 interconnected by a plurality oftransverse steps or bars 136 with the upper most step of the movablesection 124 being hingedly attached to the lower end of the stationarysection 122 by the use of a hinge structure 138.

The movable section 124 is swung pivotally about the hinge axis of thehinge 138 by a gear 140 attached to the movable section 124 coincidentwith the hinge axis. The gear 14 is meshed with a worm drive gear 142 onthe end of an elongated drive shaft 144 driven by a suitable reversibleelectric motor or the like 146 which is mounted on the stationarysection 122 so that when the motor 146 is actuated in either direction,corresponding swinging movement off'the movable section 124 will occur.

FIGS. 10-12 illustrate another embodiment of the boat ladder generallydesignated by the numeral 150 and which includes a stationary section152 and a movable section 154. The stationary section 152 includes aplurality of steps or bars 156 rigidly mounted on the a stern 158 of theboat hull with the steps being of any suitable configuration andattached rigidly to the boat hull in any desired manner. The movablesection 154 includes a pair of side members 160 interconnected by atransverse step or bar 162 which defines a generally U-shapedconfiguration having the ends of the side members 160 pivotallysupported from a pair of brackets 164 by a pivot pin, bolt or the like166. Pivotal movement or swinging movement of the movable section 154 isobtained by a fluid pressure operated piston and cylinder assembly 168interconnecting the side members 160 and the stern 158 of the boat hullso that as the piston and cylinder assembly 168 is extended andretracted, the movable section 54 is moved from the retracted positionillustrated in full lines to the extended position illustrated in fulllines to the extended position illustrated in full lines to the extendedposition illustrated in broken lines in FIGS. 11 and 12. Suitableconduits 170 are provided for connection with the piston and cylinderassembly 168 to extend and retract the piston rod. The piston andcylinder assembly has one end attached to the side member 160 by apivotal connection 172 and the other end is pivotally attached to abracket 174 by a pivotal connection 176 so that forces exerted by thepiston and cylinder assembly 168 will be transmitted through the bracket174 to the boat hull. The transverse step or bar 162 will be constructedin substantially the same configuration as the steps 156 and will beretracted to a position out of the water except when in use and when themovable section is extended, the transverse step 162 will be below thebottom of the hull or belowwater level when the boat is floating in thewater to faciliate access to the interior of the boat.

FIGS. 13 and 14 illustrate another embodiment of the invention generallydesignated by numerals 180 and which includes a stationary section 182and a movable section 1. The stationary section 182 includes a recess186 defined in the bottom portion of the side or how portion 188 of theboat hull having a transverse step or bar 190 formed therein inalignment with a vertically spaced inwardly extending recess 192 whichdefines a step to provide access to the interior of the boat. Themovable section 184 includes a panel 194 which generally forms acontinuation of the boat hull 188 when in closed position with the loweredge of the panel 194 being hinged to the lower edge of the recess 186by a hinge pin or other hinge means 196 for pivoting movement from theretracted position illustrated in full lines in FIG. 14 to the extendedposition illustrated in broken lines. The inner surface of the panel 194is provided with a transversely extending step or bar 198 which extendsbetween two side walls 200. The side walls 200 are disposed alongsidethe end walls of the recess 186 when the movable section 184 isretracted.

, A pair of fluid pressure-operated piston and cylinder assemblies 202extend between pivot connections 204 with the side walls 200 andbrackets 206 on the inner wall of the recess 186 so that when the pistonand cylinder assemblies 202 are extended and retracted, the movablesection 184 will be pivoted or swung between an extended and retractedposition. Suitable conduits, pressure supply means and control valvedevices will be provided for selectively extending and retracting themovable section 184.

FIG. 15 illustrates a safety circuit which prevents the ladder operationat high speeds and also prevents engine operation when the ladder isextended and schematically illustrates the motor which extends andretracts the movable section of the ladder either by mechanicalconnection, hydraulic operation or pneumatic operation, or the like,with the motor being designated by numeral 210. The motor iselectrically connected to the battery 212 in the usual manner and thebattery is electrically connected to the engine ignition circuit 214through an ignition safety switch 216 that is normally open when theladder is extended. The battery 212 is connected to one side of themotor through a throttle limit switch 218 which is normally open at highspeed and a ladder switch 220 mounted on the instrument panel or otherconvenience location accessible to the operator of the boat and aparallel ladder switch 222 located on the stern of the boat hull or .onany other convenient location on the boat hull accessible to the persondesiring to extend the ladder. Thus, the ladder may be extended byeither the operator of the boat or the person desiring to gain accessinto the boat from a position in the water or from a position exteriorlyof the boat when the boat is on a transporting trailer. Any suitablearrangement may be provided for maintaining the throttle limit switchopen at high speed settings of the throttle thereby preventingenergization of the motor 210 unless the throttle setting has beenlowered, thus enabling the switch 218 to close. Correspondingly, whenthe ladder is extended, an interlock is provided to prevent the ignitionsafety switch from being closed.

Thus, the ladder may be power-operated by a remote or local station orstations in the boat or out of the boat as may be desired. As indicated,the mounting of the ladder may be at the stern, side or bow of the hull,the drives may includes electric motor, hydraulic, manual, or anycombination thereof, operating from the existing electrical system ofthe boat. Various materials which are corrosion resistant and providedwith adequate strength may be employed in constructing the ladder. Theladders basically are of the telescoping extending and retracting typeand the swinging extending and retracting type and in both types of theinvention, a movable section is out of the water during movement of theboat at normal speeds and disposed above the bottom of the boat so thatit will not interfere with movement of the boat onto or off of atransporting trailer.

All forms of the invention may employ the movable section and astationary section which may be an attachment to a boat hull orcompletely or partially built into the boat hull. The variousembodiments of the ladder will include the position locking device toreleasably retain the movable sections in either extended or retractedpositions when power is not being applied thereto. The position lockingdevice may be in the form of a spring loaded detent associated with thetelescopic membrs as illustrated in FIG. or a similar spring loadeddetent associated with the hinged movable section for retaining it inposition. The spring bias on the detent may be adjustable by providingan adjustment screw engaging the end of the spring remote from thedetent which may be in the form of a pin or peg or a spherical balldetent, or the like. Standard attachment brackets may be provided, suchas an anchor flange for securing the attaching brackets to the boat hulland the attaching brackets themselves may be telescopingly adjustable oradjustable in any other manner to affix the boat ladder in substantiallya vertical position. The electric motor and fluid pump and conduits,electric switch and other control apparatuses associated therewith areoriented in an accessible manner with the electric motor beingreversible to power the movable section toward an extended position ortoward a retracted position with the safety circuit assuring that theladder will only be extended at the appropriate time, such as when theboat is either dead in the water or travelling at very low speed.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention.

What is claimed as new is as follows:

1. A boat ladder combined with a pleasure boat to fa cilitate a usergetting into or out of a pleasure boat when in the water away from adock and when on a transporting trailer or the like comprising astationary section rigid with respect to the boat hull, a movablesection movable mounted with respect to the stationary section formovement between extended and retracted positions, each of said sectionsincluding at least one transverse member defining a step with the stepon the movable section being moved to a lower position below the boathull when the movable section is in its extended position, the step onthe stationary section cooperating with the step of the movable sectionto span the distance from the top edge of the boat hull to the waterwhen fully extended, said sections being out of the water when themovable section is fully retracted, and power means including motormeans interconnecting the stationary section and movable section to moveand retain said movable section in at least one direction of movementand control means for the movable section operable both interiorly ofand exteriorly of the boat hull.

2. The structure as defined in claim 1 wherein said movable section isreciprocally mounted with respect to the stationary section forsubstantially vertical movement between extended and retractedpositions.

3. The structure as defined in claim 2 wherein said stationary sectionincludes substantially vertically disposed guide members telescopinglyengaged with portions of the movable section.

4. The structure as defined in claim 3 wherein said means moving themovable section in at least one direction including a fluidpressure-operated piston and cylinder assembly interconnecting themovable section and stationary section, said piston and cylinderassembly being double acting and communicated with a source of fluidpressure for power operation of the movable section between the extendedand retracted positions.

5. The structure as defined in claim 1 wherein said movable section ishingedly connected with the stationary section for pivotal swingingmovement.

6. The structure as defined in claim 5 wherein said meansinterconnecting the movable section and the stationary section includesa gear mechanism having drive gear means mounted on the stationarysection and driven gear means mounted on the movable section having acenter of rotation coincident with the axis of movement of the movablesection to swing the movable section when the drive gear means isrotated.

7. The structure as defined in claim 6 wherein said stationary sectionincludes a plurality of vertically spaced and aligned steps mountedalongside of the boat hull, said steps being interconnected by sidestiles, said drive gear means being in the form of a drive gear mountedon one of said stiles, drive motor means connected to the drive gearmounted on said stile, said driven gear means including a driven gearmeshing with the drive gear with the driven gear being rigid with themovable section for swinging the movable section from a positionalongside of the stationary section to a position depending therefrom,said movable section including a plurality of vertically spaced stepsinterconnected by said stiles, the lower ends of the stationary andmovable section being above the waterline when the movable sect-ion isin retracted position and a substantial portion of the movable sectionbeing below the waterline when the movable section is in extendedposition.

8. The structure as defined in claim 7 wherein said means retaining saidmovable section in at least one direction of movement including thedrive gear and driven gear, said drive gear being in the form of a wormgear mounted on one of said stiles, said driven gear 9. The structure asdefined in claim 5 wherein said means interconnecting the movablesection and stationary section includes a fluid pressure operated pistonand cylinder assembly for swinging the movable section about its hingeaxis.

10. The structure as defined in claim 1 wherein said stationary sectionis an integral part of the boat hull, said movable section being housedwithin the boat hull when in retracted position with the exterior of themovable section generally matching the exterior surface of the boathull.

1. A boat ladder combined with a pleasure boat to facilitate a usergetting into or out of a pleasure boat when in the water away from adock and when on a transporting trailer or the like comprising astationary section rigid with respect to the boat hull, a movablesection movable mounted with respect to the stationary section formovement between extended and retracted positions, each of said sectionsincluding at least one transverse member defining a step with the stepon the movable section being moved to a lower position below the boathull when the movable section is in its extended position, the step onthe stationary section cooperating with the step of the movable sectionto span the distance from the top edge of the boat hull to the waterwhen fully extended, said sections being out of the water when themovable section is fully retracted, and power means including motormeans interconnecting the stationary section and movable section to moveand retain said movable section in at least one direction of movementand control means for the movable section operable both interiorly ofand exteriorly of the boat hull.
 2. The structure as defined in claim 1wherein said movable section is reciprocally mounted with respect to thestationary section for substantially vertical movement between extendedand retracted positions.
 3. The structure as defined in claim 2 whereinsaid stationary section includes substantially vertically disposed guidemembers telescopingly engaged with portions of the movable section. 4.The structure as defined in claim 3 wherein said means moving themovable section in at least one direction including a fluidpressure-operated piston and cylinder assembly interconnecting themovable section and stationary section, said piston and cylinderassembly being double acting and communicated with a source of fluidpressure for power operation of the movable section between the extendedand retracted positions.
 5. The structure as defined in claim 1 whereinsaid movable section is hingedly connected with the stationary sectionfor pivotal swinging movement.
 6. The structure as defined in claim 5wherein said means interconnecting the movable section and thestationary section includes a gear mechanism having drive gear meansmounted on the stationary section and driven gear means mounted on themovable section having a center of rotation coincident with the axis ofmovement of the movable section to swing the movable section when thedrive gear means is rotated.
 7. The structure as defined in claim 6wherein said stationary section includes a plurality of verticallyspaced and aligned steps mounted alongside of the boat hull, said stepsbeing interconnected by side stiles, said drive gear means being in theform of a drive gear mounted on one of said stiles, drive motor meansconnected to the drive gear mounted on said stile, said driven gearmeans including a driven gear meshing with the drive gear with thedriven gear being rigid with the movable section for swinging themovable section from a position alongside of the stationary section to aposition depending therefrom, said movable section including a pluralityof vertically spaced steps interconnected by said stiles, the lower endsof the stationary and movable section being above the waterline when themovable section is in retracted position and a substantial portion ofthe movable section being below the waterline when the movable sectionis in extended position.
 8. The structure as defined in claim 7 whereinsaid means retaining said movable section in at least one direction ofmovement including the drive gear and driven gear, said drive gear beingin the form of a worm gear mounted on one of said stiles, said drivengear being in the form of a worm pinion rigid with the movable sectionfor swinging the movable section when the drive motor is actuated andretaining the swingable section in position when the drive motor meansis not actuated, and control means for the drive motor means operableboth interiorly and exteriorly of the boat hull, and an ignition safetyswitch normally in open condition when the ladder is in extendedposition to prevent operation of the engine ignition circuit when theladder is extended.
 9. The structure as defined in claim 5 wherein saidmeans interconnecting the movable section and stationary sectionincludes a fluid pressure operated piston and cylinder assembly forswinging the movable section about its hinge axis.
 10. The structure asdefined in claim 1 wherein said stationary section is an integral partof the boat hull, said movable section being housed within the boat hullwhen in retracted position with the exterior of the movable sectiongenerally matching the exterior surface of the boat hull.